probability

If there are 420 seats available in a lottery and there are 4 preference levels in order: 20 % of seats go to top students, then employees children, then military, then 25% of seats go to siblings. If my child was in category 1 (20%) and category 4 (sibling) what are the chances that she would not be chosen at all? Assume 20 seats to employee and 20 seats to military.